Pulsar radiation as polarized shot noise.

Pulsar radiation can be reasonably modeled as amplitude-modulated shot noise for which the amplitude modulations correspond to the subpulses and micropulses that comprise the structure of single pulses. The noise fluctuates on nanosecond time scales and therefore has a bandwidth typical of pulsars, namely, 1 to 10 GHz. Some statistics of the corresponding signal in a narrow-band receiver system are calculated, including the intensity modulation index of the narrow-band noise from which it can be determined whether or not the noise has Gaussian statistics. Departures from Gaussian statistics can occur if intensity variations are due primarily to changes in the number of particles radiating coherently at any instant. If the temporal density of shot pulses is sufficiently high, however, only Gaussian statistics will be observed, meaning that extensive incoherent addition occurs in the generation and the propagation of the radiation. The first and second moments of the Stokes parameters of narrow-band signals are derived for both time-independent and time-variable polarization. It is shown how the polarization properties of short-time scale structure can be determined from the autocorrelation functions of the Stokes parameters.